Floating roof for liquid storage tanks



Aug. 9, 1932.

J. H. WIGGIN S iLQATING ROOF FOR LIQUID STORAGE TANKS- Filed March 51, 1930- QTTORNE 1 Patented Aug. 9, 1932' curren Sim-ms m,om,

' 7 10m: n. wreems, or oxmnoim meme poor. iron mourn aromas mim cs imam ma men a1, 1930. Serial no.- 440,530.

- Ihis invention relates to floating roofs for liquid storage tanks of the type that comprise a substantially disk-shape portion that covers the major portion of the hquid in the G tank, andan upwardl -projecting, rigid, an-

7 nular rim at the perip eral edge of said disk sha ed portion.

eretofore the rims of such tank roofs have been formed from curved metal lates -3 reinforced andoonnected to the disk snaped portion of the roof bycurved an leirons connected to the web of the rim 'y; welds extending around the entire circumference of the roof. The cost of curving the angles and producing two complete circumferential welds constitutes an item of considerable importance in the cost of building the roof, and

, eliminate the curving operation heretofore regained in constructing the annular rim of a eating roof for liquid storage tanks. Another object is to reduce the weight of a floating roof provided with an annular rim and also overcome the necessity of forming two complete circumferential welds in mama facturing the rim.

' And still another object is to provide a floating roof which is of such construction that straight flanged members of standard shape may be used to form the rims of roots of various diameters. s

Figure 1 is a fragmentary top plan View of a floating roof for liquid storage tanks embogying my invention. v

igure 2 is a sectional view, taken on the line 22 of Figure 1, looking in the direction indicated by the arrows; and

Figure 3 is a perspective view, illustrating my preferred method of combining the U- shaped or channel-shaped members that com stitute the rim of the roof.

In the drawing A designates a tank roof that comprises a substantially disk-shaped portion that floats upon the 'liquidconfined 1n the tank, and B designates as anentirety an upwardly-projecting 'drim atthe erlpheral edge of the r005 The space etween said rim and the side wall'@ of the tank is closed by aistructure commonly referred to as a seal, which is herein illustrated as comprising shoe members D arran ed in sliolin engagement with the side wa of the ta an sustained by swinging hangers E on the rim, and a flexible element F, usuall formed from a substantially annular-shape piece of gas-ti ht fabric havin its outer edge attache by a gas-tight int to the shoe members D and having its inner edge attached by a gas tight joint to the rim B of the roof. My present invention relates solely to the construction of the rim B of the roof, and there- 'fore, it is immaterial what means is employed to close the space between said rim and the side "wall oil the tank.

Instead of forming-the rim of the roof from curved plates and curved angles, as has heretofore been theusual practice,- rim B of an improved roof from a plurality 'of relative y short members of standard shape that can be produced easily and at a tion and joined together and attached to the roof without the necessity of forming complete circumferential welds Said members formthe I low cost by a simple straight flanging operaso I I are formed from flat plates provided with integral, straight'flanges, and said members are straight circ'iimferentially of the roof and are arranged at the peripheral edge of the 3 roof in such a way as to produce a substantially polygonal-like structure that can be easily changed or modified to ads t it to circles of various diameters by simp y varying the angle between any two sides of the polygon Said members are arranged in endwise relation around the circumference of the roof, andthey may either be disposed in abutting relation and connected together b butt straps, or they may be disposed in su stantially telescopic relation.

In the preferred form of my invention, as herein illustrated, the rim B of the roof is made up of a plurality of relatively short channel-shaped members or U-shaped members G, attached to the peripheral portion of the roof in such a way that they act collectively to form a vertically-disposed web of substantially annular form projectin upwardly from the top side of the roof an provided at its top and bottom edges with integral, laterallyrojecting flanges that impart the require rigidity or stifl'nessto the .rim and also enable the rim to be easily attached to the roof. Any suitable or preferred means may be used'for connecting the members G together and for attaching said members to the roof, and the particular manner in which said members are combined or arranged relatively to each other is immaterial, so long as said members. are dis osed in substantially endwise relation an extend circumferentially around the peripheral edge of the portion .of the roof that floats upon the li u1d in the tank. a

h prefer, however, to construct the rim from straight U-shaped members arranged horizontally, as shown in Figure 3, and proportioned so that one end of each memberwill telescope inside of an adjacent member,

and the other end of said member will telescope outside of the member adjacent said enlarged end. When the members G are arran ed in this manner the vertical webs 1 of sai members will act collectively to form a substantially vertically-disposed annular rim, the 'top flanges 2 of said members will act collectively toform an integral, inwardly-projecting reinforcing flange at the top edge of said web, and the flanges 3 of said members will act collectively to form an inwardly-projecting, integral flange at the bottom edge of said web that is used to attach'the'rim to the peripheral edge of the portion A of the roo After the members G have been arranged in telescopic relation on the peripheral edge portion of the roof A, the overlapping parts at the ends of said members are joined together by welded joints and the bottom flanges 3 of said members are connected by welded joints to the roof on which said-bottom flanges rest. As previously stated, however, any other suitable or preferred means may be used to permanently join the members that constitute the rim and to attach said rim to the disk-sha ed portion A of the roof.

The a ove described method of constructing the rim B reduces the cost of manufac turing the roof, as it overcomes the necessity of bending angle irons on an are or radius, and it overccmes the necessity of forming two continuous ring-shaped welds that ex .tend unbrokenly around the entire circumference of the roof. A rim B of the construction herein illustrated is rigid enough to successfully perform the function for which it is designed, but it is considerably lighter in weight than a rim provided at its top and bottom edgeswith flanges formed b comed, the angular relationship of the members G can be easily changed, so as to produce a substantially circular rim of any desired diameter. This is a very desirable feature of my roof, as it overcomes the necessity of using special shapes for roofs of different diameters, thereby materially simplifying the operation of fabricating the roof.- As the members G are of substantially U-shape or channel shape, the can be ne'sted together when the parts 0 shaped to the point where the roof is to be installed, thus effecting a considerable savmercially rolled angles. As previous y statthe roof are in transit 7 from the place where said parts are cut or ing in the space required to ship the parts of the roof.

' Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A floating roof for liquid storage tanks, provided at its peripheral edge with a flanged rim made up of a p urality of relatively short plates arranged in endwise relation and provided with integral, laterally-projecting flanges. v

,2. A floating roof for liquid storage tanks,

provided at its peripheral edge with a vertically-disdosed rim made up of a plurality of relatively short, channel-shaped members arranged horizontally in endwise relation.

3. A floating roof provided with a rim. composed of a plurality of substantially channel-shaped members arranged horizon tally with their end portions in over-, lapping relation and having their bottom flanges attached to the roof.

'4. A roof for liquid storage tanks, com-.

prising a substantially disk-shaped portion that floats upon the liquid in the tank, and an 11 wardly-projecting rim at the peripheral e ge of said disk-shaped portion made up of horizontally-disposed channelshaped members arranged in endwise relation with the ends oftheir webs and flanges lapped and permanently connected together, the bottom flanges'of. said members being attached to said disk-shaped portion. 7

Y JOHN H. WIGGINS. 

